JP2006264240A - Energy absorbing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an energy absorbing member capable of maintaining excellent energy absorbing performance as a whole by improving adhesion between a metallic layer and a fiber-reinforced resin layer, in the case of composing the energy absorbing member from a metal/fiber-reinforced resin composite material. <P>SOLUTION: The energy absorbing member composed of the metal/fiber-reinforced resin composite material is made by bonding the metallic layer and the fiber-reinforced resin layer with an intermediate resin layer placed between them and integrating them wherein the intermediate resin layer contains thermoplastic resin particles having an average diameter of 3 to 10 μm and an imidazole silane compound. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an energy absorbing member made of a metal / fiber reinforced resin composite material, and in particular, to improve the adhesiveness between a metal layer and a fiber reinforced resin layer, and to achieve energy absorption performance that can reliably exhibit the target energy absorption performance as a whole. It relates to members.

  A composite material in which metal and fiber reinforced resin are laminated and bonded together is a material that can exhibit both the excellent impact resistance, conductivity, etc. possessed by the metal, and the excellent lightness and high mechanical properties possessed by the fiber reinforced resin. Known as.

  In particular, as an energy absorbing member, an aluminum alloy energy absorbing member is known from the viewpoint of weight reduction, but the aluminum alloy is lower in strength and elastic modulus than a steel material, so the energy absorption amount is small. There's a problem. Therefore, an energy absorbing member is known in which a fiber reinforced resin is bonded and integrated with an aluminum alloy so as to improve the energy absorbing performance while maintaining light weight. Thus, in order to improve the energy absorption amount by bonding and integrating the fiber reinforced resin, it is required that the fiber reinforced resin is well bonded to the metal layer until it absorbs energy and breaks.

  However, in an energy absorbing member composed of a metal / fiber reinforced resin composite material simply formed by laminating and bonding a metal layer and a fiber reinforced resin layer, delamination may occur between the metal layer and the fiber reinforced resin layer. There is a problem that a predetermined energy absorption performance as a target cannot be expressed. In particular, when the metal layer is made of a difficult-to-adhere metal such as an aluminum alloy or a titanium alloy, delamination is likely to occur, and surface treatment such as chemical etching is required to improve the adhesion. The problem of deterioration and high cost remains, and it has not been put into practical use.

In order to improve the adhesion of the metal layer, surface treatments such as forming an anodized film have been proposed (for example, Patent Document 1 and Patent Document 2), but the adhesion between the metal and the adhesive is improved. However, the adhesiveness between the adhesive and the fiber reinforced resin is not necessarily improved. In addition, although a technique for increasing the toughness of the adhesive itself has been proposed (for example, Patent Document 3 and Patent Document 4), the adhesive layer and the fiber reinforced resin layer are suppressed although destruction in the adhesive layer is suppressed. The peel strength at the interface with the film is not necessarily improved.
JP 2002-129387 A JP-A-7-252687 JP 58-189277 A JP 2004-263104 A

  Therefore, the object of the present invention is to exhibit excellent characteristics of each layer by improving the adhesion between the metal layer and the fiber reinforced resin layer, particularly when the energy absorbing member is composed of a metal / fiber reinforced resin composite material. An object of the present invention is to provide an energy absorbing member that can solve problems such as delamination between both layers while maintaining excellent energy absorption performance as a whole.

  In order to solve the above problems, an energy absorbing member according to the present invention is an energy absorbing member composed of a metal / fiber reinforced resin composite material in which a metal layer and a fiber reinforced resin layer are bonded and integrated through an intermediate resin layer. The intermediate resin layer contains thermoplastic resin particles having an average particle diameter of 3 to 10 μm and an imidazolesilane compound.

  In this energy absorbing member, the boundary portion (interface vicinity portion) between the intermediate resin layer and the fiber reinforced resin layer is a mixture in which the thermoplastic resin constituting the particles and the reinforced fibers of the fiber reinforced resin layer are mixed. It is preferable to form a layer.

  The thermoplastic resin particles are preferably present in the intermediate resin layer at least partially in the form of a continuous phase due to fusion of particles or the like.

  The matrix resin of the fiber reinforced resin layer and the base resin of the intermediate resin layer are preferably made of the same kind of resin (preferably, the same resin). For example, the matrix resin of the fiber reinforced resin layer and the base resin of the intermediate resin layer are preferably made of the same type or the same thermosetting resin (for example, epoxy resin).

  Various metals can be adopted as the metal layer, but high-strength steel, aluminum alloy, titanium alloy and the like are preferably used from the viewpoint of weight reduction. In particular, the effect of the present invention is particularly great when the layer includes a hard-to-bond metal such as an aluminum alloy or a titanium alloy. The shape of the metal layer is not particularly limited, and may be a simple layer shape (plate shape) or a shape such as a box-shaped cross section. In any case, the present invention can be applied.

  Various reinforcing fibers can be used as the reinforcing fiber of the fiber-reinforced resin layer. In particular, the carbon fiber has a high specific strength and a high specific modulus, and has excellent mechanical properties. If it comprises, it will become easy to obtain the characteristic more excellent as the whole energy absorption member, and it will become easy to control the characteristic.

  The energy absorbing member according to the present invention is not particularly limited as long as it is used for energy absorption, and includes any form of energy absorbing member in all fields.

  In such an energy absorbing member according to the present invention, the intermediate resin layer contains thermoplastic resin particles having a particle diameter in a predetermined range, so that the thermoplastic resin particles ensure a predetermined thickness of the intermediate resin layer. An intermediate resin layer having a predetermined thickness is reliably interposed between the metal layer and the fiber reinforced resin layer. In addition, since the thermoplastic resin particles are blended in the intermediate resin layer, the toughness of the intermediate resin layer itself can be increased.

  The metal layer and the fiber reinforced resin layer are bonded and integrated through this intermediate resin layer, but the intermediate resin layer contains an imidazole silane compound, thereby improving the adhesion to the metal and making it difficult to adhere to a metal. In contrast, good adhesiveness can be expressed, and the adhesiveness between the intermediate resin layer and the metal layer is greatly improved.

  Further, since the intermediate resin layer contains thermoplastic resin particles having a fine particle diameter within a predetermined range, in the vicinity of the interface with the fiber reinforced resin layer, more or less thermoplastic particles are present between the reinforced fibers of the fiber reinforced resin layer. An invading form can be easily formed. That is, the boundary portion between the intermediate resin layer and the fiber reinforced resin layer can be formed in a mixed layer in which the thermoplastic resin particles and the reinforced fibers of the fiber reinforced resin layer are mixed. In such a form, for example, if the intermediate resin layer and the fiber reinforced resin layer are simultaneously formed at a temperature equal to or higher than the melting point of the thermoplastic resin particles, the particles are easily at least partially in a continuous phase form by fusion or the like. It is a series. If such a form appears, the thermoplastic resin that is at least partially in the form of a continuous phase by fusion or the like is formed at the interface between the intermediate resin layer and the fiber reinforced resin layer. It exists across both layers, and the anchor effect will be exhibited from any layer. Due to this anchor effect, the adhesion between the intermediate resin layer and the fiber reinforced resin layer is also reliably and significantly improved. Furthermore, when the outermost layer is a fiber reinforced resin layer, it is preferable that the outermost layer of the fiber reinforced resin layer is subjected to water repellent treatment to form a water repellent layer. When the energy absorbing member of the present invention is exposed to high humidity or warm water, there is a concern that the adhesion between the metal and the fiber reinforced resin may deteriorate due to moisture absorption or water absorption of the fiber reinforced resin layer. This is because moisture absorption or water absorption can be suppressed and adhesion deterioration can be prevented.

  The metal layer and the fiber reinforced resin layer are bonded and integrated with a strong adhesive force that does not cause peeling through the intermediate resin layer, so that the metal layer has excellent impact resistance and the like. Both the excellent lightweight properties and mechanical properties of the reinforced resin layer can be expressed stably, and the fiber reinforced resin layer is securely bonded to the metal layer through the intermediate resin layer until it breaks. Thus, the target predetermined energy absorption performance is surely exhibited.

  Thus, according to the energy absorbing member of the present invention, the metal layer and the fiber reinforced resin layer are bonded and integrated through the intermediate resin layer containing the thermoplastic resin particles having a predetermined particle diameter and the imidazole silane compound. Thus, an energy absorbing member made of a metal / fiber reinforced resin composite material that can greatly improve the adhesiveness and can exhibit excellent energy absorbing performance without causing delamination can be put into practical use.

  Moreover, since predetermined energy absorption performance can be expressed without performing special surface treatment or the like, the energy absorption member can be easily manufactured at high cost with high productivity.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an energy absorbing member according to an embodiment of the present invention. In FIG. 1, 1 shows the whole energy absorbing member, and this energy absorbing member 1 is a metal energy as a metal layer 2 formed in an arbitrary required shape (formed in a box-shaped cross section in the illustrated example). It has an intermediate resin layer 4 that is interposed between the absorbent member, the fiber reinforced resin layer 3, and the metal layer 2 and the fiber reinforced resin layer 3 to bond and integrate the metal layer 2 and the fiber reinforced resin layer 3. . However, the metal layer 2 may be disposed so as to form the outermost layer as illustrated, or may be disposed in an inner layer viewed from the entire member, a fiber reinforced resin layer, or the like. Further, the shape and thickness of the metal layer 2 may be set in accordance with the required thickness and energy absorption performance of the entire member, and the adhesive strength with the fiber reinforced resin layer 3 is greatly improved as described later. In addition, it may be set according to the mechanical characteristics and energy absorption performance required for the member. However, from the viewpoint of reducing the weight of the energy absorbing member 1 as a whole, a thin and small-sized one is preferable as long as dynamic characteristics are not hindered. The energy absorption performance is obtained by, for example, receiving a both-end portion of the energy absorption member 1 with a support member such as a round bar (P point), and applying a shock load F from above, so-called a three-point bending test, and the fiber reinforced resin layer 3 By performing the impact load F until the fracture occurs, the energy absorption performance of the entire member expressed mainly by the tensile strength of the fiber reinforced resin layer 3 can be measured.

  The intermediate resin layer 4 contains thermoplastic resin particles having a predetermined particle diameter (average particle diameter of 3 to 10 μm) and an imidazolesilane compound. The fiber reinforced resin layer 3 is composed of a composite material composed of reinforced fibers and a matrix resin (for example, a thermosetting resin such as an epoxy resin).

  Examples of such an adhesive structure between the intermediate resin layer 4, the metal layer 2, and the fiber reinforced resin layer 3 are shown in FIGS. FIG. 3 is a more preferable example.

  FIG. 2 shows the portion A of FIG. 1, and in this example, between the metal layer 2 and the fiber reinforced resin layer 3 including the reinforcing fiber (group) 5 and the thermosetting matrix resin 6, An intermediate resin layer 4 serving as an adhesive resin layer including a thermoplastic resin 8 (a thermoplastic resin continuous phase 8a and a thermoplastic resin particle phase 8b) with a thermosetting resin 7 as a base resin is interposed. When the thermoplastic resin particles having a predetermined particle diameter are blended in the intermediate resin layer 4, the particles serve as a spacer to ensure a desired thickness of the intermediate resin layer 4, and the metal layer 2 and the fiber reinforced resin layer 3. A desirable interlayer thickness can be ensured between Moreover, the intermediate resin layer 4 can be toughened by blending the thermoplastic resin particles, and the contained particles can also exhibit a pinning effect against cracks, for example. The thermoplastic resin particles having the predetermined particle diameter contained in the intermediate resin layer 4 are at least partially in a continuous phase form (linear or film-like continuous phase form) by, for example, fusion as shown in the figure. The thermoplastic resin continuous phase portion 8a and the thermoplastic resin particle phase portion 8b that are substantially left in the form of particles are mixed. Thus, by including the thermoplastic resin in the intermediate resin layer 4 in the form of a continuous phase, the adhesion between the metal layer 2 and the fiber reinforced resin layer 3 is improved. In particular, when a stress in a peeling mode such as peeling from the fiber reinforced resin layer 3 is applied to the metal layer 2, the thermoplastic resin in the intermediate resin layer 4 has the form of the continuous phase 8a. It is considered that it acts as an anchor for the thermosetting base material resin 7 to be configured, and the adhesiveness is improved. Here, the thermosetting matrix resin 6 constituting the fiber reinforced resin layer 3 and the thermosetting matrix resin 7 constituting the intermediate resin layer 4 may have the same resin composition or different thermosetting resins. It may be.

  The thermosetting resin 7 constituting the intermediate resin layer 4 contains an imidazole silane compound. By including this imidazolesilane compound, the adhesiveness between the intermediate resin layer 4 and the metal layer 2, particularly the metal layer 2 containing a difficult-to-bond metal such as an aluminum alloy is improved. In addition, a decrease in adhesiveness after exposure to high temperature and high humidity is suppressed, and the resistance to environmental exposure can be improved. The blending amount of the imidazole silane compound in the thermosetting resin is preferably 0.1% by weight or more and 2.0% by weight or less with respect to the weight of the resin composition. That is, when the amount of the imidazole silane compound is less than 0.1% by weight, the effect of improving adhesiveness is small, which is not preferable. If it exceeds 2.0% by weight, especially when an epoxy resin is used as the thermosetting resin, the imidazole silane compound also acts as a curing agent or a curing accelerator, so that curing is excessively accelerated. Therefore, it is not preferable. In this case, it is also one of preferable usage forms that a solution obtained by melting an imidazolesilane compound in an organic solvent such as ethanol is applied to a metal adhesion surface, dried and subjected to a surface treatment. Thus, the purpose of use of the imidazolesilane compound in the present invention is to improve the adhesion to the metal layer 2 in particular, and is used as a curing agent or curing accelerator for a thermosetting resin or as a rust preventive for metals. is not.

  FIG. 3 shows a more preferable embodiment. That is, in the energy absorbing member 11 shown in FIG. 3, the intermediate resin layer 12 is formed at the boundary between the fiber reinforced resin layer 3 and the reinforced fibers 5 of the fiber reinforced resin layer 3, and the thermoplastic resin, particularly the continuous phase heat. The mixed layer 12b in which the plastic resin 8a is mixed is formed unevenly. The portion closer to the metal layer 2 than the mixed layer 12b has substantially the same form as the intermediate resin layer 4 shown in FIG. Thus, by mixing the reinforcing fiber 5 and the thermoplastic resin continuous phase 8a, the thermoplastic resin continuous phase 8a acts as an anchor for the reinforcing fiber group 5, and the intermediate resin layer 12 and the fiber reinforced resin layer 3 Adhesion is greatly improved. It is more preferable that each thermoplastic resin continuous phase 8a is in contact with a plurality of reinforcing fibers 5.

  The thickness of the intermediate resin layer 12 is preferably 15 μm or more and 150 μm or less, for example, and the maximum thickness of the mixed layer 12b is preferably 10 μm or more and 100 μm or less. FIG. 4 shows the thickness of the intermediate resin layer 12 as Ta and the thickness of the mixed layer 12b with the thermoplastic resin continuous phase 8a as the reinforcing fiber group 5 as Tpf. Ta and Tpf can be measured by observing the cross section of the composite material with an optical microscope, a microscope using a CCD, SEM, and TEM.

  If the thickness Ta of the intermediate resin layer 12 is less than 15 μm, the intermediate resin layer 12 is too thin and the layer is easily broken, which is not preferable. On the other hand, when the thickness is larger than 150 μm, the intermediate resin layer 12 is too thick, so that the weight of the intermediate resin layer 12 increases and the weight reduction as a composite material is impaired.

  Furthermore, the thickness Tpf of the mixed layer 12b in which the reinforcing fiber 5 and the thermoplastic resin continuous phase 8a are mixed may be less than 10 μm, but is preferably 10 μm or more because the adhesiveness is further improved. On the other hand, if it is thicker than 100 μm, it is not preferable because it is too thick and the weight of the intermediate resin layer 12 increases. Moreover, it is not preferable to mix the thermoplastic resin continuous phase 8a thicker than 100 μm between the reinforcing fibers because it may be very difficult from the viewpoint of molding.

  Regarding the thermoplastic resin particles blended in the intermediate resin layer 12, it is preferable that a continuous phase having the above-described continuous shape and a particle shape having an average particle diameter of 3 μm or more and 10 μm or less are mixed. The intermediate resin layer 12 is composed of a base resin 7 made of a thermosetting resin and a thermoplastic resin. The thermoplastic resin has a particle shape with an average particle size of 3 μm to 10 μm and is mixed with the thermosetting resin. Has been. By making the particle shape 3 μm or more and 10 μm or less, it is easy to process the intermediate resin layer 12 into a film shape or the like before molding. Further, in the curing and molding process, the thermoplastic resin is interposed between the reinforcing fibers. It becomes easy to form the layer 12b in which the reinforcing fiber and the thermoplastic resin are mixed after molding. For this reason, it is preferable that the thermoplastic resin mixed in the particle shape forms a continuous phase having a continuous shape, and a part of the thermoplastic resin is present in the particle shape.

In addition, the resin composition itself constituting the intermediate resin layer 12 in the present invention is measured based on ASTM D 5045-96 “Standard Test Methods for Plane-Strain Fracture Toughness and Strain Energy Rate of Matter Release”. The rate (Strain Energy Release Rate) G _IC is preferably 400 J / m ² or more and 1000 J / m ² or less. A G _IC of less than 400 J / m ² is not preferable because the strain energy release rate is too low and the destruction of the intermediate resin layer 12 proceeds relatively easily. G _IC can be improved by mixing the thermoplastic resin in the intermediate resin layer 12 in a continuous phase having a continuous shape. Further, by increasing the mixing amount of the thermosetting resin of the thermoplastic resin, it is possible to improve the G _IC. On the other hand, in order to make G _IC larger than 1000 J / m ^2, it is necessary to mix a larger amount of thermoplastic resin. However, if the amount of the thermoplastic resin mixed is too large, the resin composition may have a film shape or the like. This is not preferable because it becomes difficult to process and there is a concern that the heat resistance or elastic modulus of the resin layer may decrease.

  In order to at least partially make the thermoplastic resin into a continuous phase by fusion or the like, it is preferable to mold at a temperature equal to or higher than the melting point (or softening point) of the thermoplastic resin particles. When the intermediate resin layer 12 and the fiber reinforced resin layer 3 are molded simultaneously in order to allow the particles to enter between the reinforced fibers, or when a cured fiber reinforced resin is used, the surface roughness is equal to or larger than the particle diameter of the particles. A method of blasting the adhesive surface can also be adopted.

  The melting point or softening point of the thermoplastic resin is preferably 200 ° C. or lower. In the present invention, the thermoplastic resin in the intermediate resin is once melted or softened by molding a composite material at a temperature equal to or higher than the melting point or softening point of the thermoplastic resin and an appropriate pressure condition. A thermoplastic resin can be easily mixed in the form of a continuous phase. When the melting point or softening point of the thermoplastic resin is higher than 200 ° C., the molding temperature of the composite material needs to be higher than 200 ° C., which is not preferable because the molding temperature becomes too high.

  In the present invention, the reinforcing fibers constituting the reinforcing fiber group include inorganic fibers such as carbon fibers, glass fibers, and alumina fibers, organic fibers such as aramid fibers and polyamide synthetic fibers, and a combination of two or more thereof. Although it can be used, carbon fiber is particularly preferable as the reinforcing fiber. Since carbon fiber has a low specific gravity, high strength, and high elastic modulus, the specific strength and specific elastic modulus are large, and the composite material of the energy absorbing member according to the present invention can be reduced in weight, increased in strength, and increased in elastic modulus. It can be preferably used, and it is easy to control energy absorption characteristics.

  In the present invention, the thermoplastic resin is selected from the group of polyamide resin, polyester resin, polycarbonate resin, styrene resin, EVA resin, urethane resin, acrylic resin, polyolefin resin, and PPS resin. At least one kind of resin is preferred. In particular, a polyamide-based resin is more preferable because it has excellent adhesion to a thermosetting resin.

  In addition, in the energy absorbing member according to the present invention, the metal constituting the metal layer is not limited to the above-described aluminum alloy. For example, high-strength steel or titanium can be used to exhibit predetermined energy absorption performance while maintaining lightness. Alloys can be used. However, the metal species to be used may be selected according to various required characteristics.

It is sectional drawing of the energy absorption member which concerns on one embodiment of this invention. It is an expanded partial sectional view which shows the structural example of the A section of the energy absorption member of FIG. It is an expanded partial sectional view which shows another structural example of each layer adhesion part of an energy absorption member.

Explanation of symbols

1, 11 Energy absorbing member 2 Metal layer (metal energy absorbing member)
3 Fiber reinforced resin layers 4 and 12 Intermediate resin layer 5 Reinforcing fibers (group)
6 Matrix resin of fiber reinforced resin layer 7 Base resin of intermediate resin layer 8 Thermoplastic resin 8a Thermoplastic resin continuous phase 8b Thermoplastic resin particle phase 12a Mixed layer of intermediate resin layer 12b near metal layer

Claims (8)

  An energy absorbing member composed of a metal / fiber reinforced resin composite material in which a metal layer and a fiber reinforced resin layer are bonded and integrated through an intermediate resin layer, wherein the intermediate resin layer has an average particle size of 3 to 10 μm An energy absorbing member comprising thermoplastic resin particles and an imidazole silane compound.   The boundary part of the said intermediate | middle resin layer and the said fiber reinforced resin layer forms the mixed layer in which the thermoplastic resin which comprises the said particle | grain, and the reinforced fiber of the said fiber reinforced resin layer were mixed. Energy absorbing member.   The energy absorbing member according to claim 1 or 2, wherein the thermoplastic resin particles are present in the intermediate resin layer at least partially in the form of a continuous phase by fusion or the like.   The energy absorption member according to any one of claims 1 to 3, wherein the matrix resin of the fiber reinforced resin layer and the base resin of the intermediate resin layer are made of the same kind of resin.   The energy absorbing member according to claim 4, wherein the same kind of resin is made of a thermosetting resin.   The energy absorbing member according to claim 1, wherein the fiber reinforced resin layer is formed of a layer containing carbon fibers.   The energy absorbing member according to any one of claims 1 to 6, wherein the metal layer is made of a metal energy absorbing member made of an aluminum alloy.   The energy absorbing member according to any one of claims 1 to 7, wherein a water-repellent layer is formed on the surface of the outermost fiber reinforced resin layer.

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